Dissecando o Navegador (Parte Final) - O Motor de Segurança, CORS e o Fantasma do OPTIONS

This article explains the browser's security engine, focusing on Same-Origin Policy (SOP), CORS (Cross-Origin Resource Sharing), and the OPTIONS preflight request. SOP prevents cross-origin data access by enforcing matching protocol, domain, and port, while CORS uses HTTP headers to selectively allow cross-origin requests. The preflight OPTIONS request acts as a safety check before potentially destructive operations, ensuring the server understands CORS rules before the actual request is sent.